The top surfaces of stationary tables have long been used to support sewing machines or other machinery used in sewing operations. A sewing machine so supported would most likely not be ideally positioned for the operator's comfort during use. The long-term use of an unsuitably positioned sewing machine can result, for example, in physical discomfort and strain for the operator or, in extreme cases, "cumulative trauma injuries".
The need for a work station that was adjustable, both vertically and angularly, to a comfortable position for the operator has been recognized. Conventionally, as known in the art, the so-called adjustable work station has a top surface that is vertically adjustable by two cylinders located on either side of the station. Typically, these cylinders are driven in the vertical direction by hydraulic or pneumatic means.
The adjustable work stations as known in the art, suffer several disadvantages. First, it is difficult to maintain equal levels of flow of the hydraulic or pneumatic working fluid to the two separate cylinders. An uneven flow of the working fluid to the cylinders will result in one side of the work station surface being raised higher than the other side. An unlevel work station surface is undesirable. Second, hydraulic and pneumatic systems are prone to leakage. Leakage in one cylinder but not in the other will result in an unlevel work station surface. Moreover, leakage of hydraulic fluids is detrimental in that it can cause damage or soiling of the workpiece materials being sewn by the sewing machine operator.